84 plus what equals 81?

This is how to calculate "84 plus what equals 81?" In other words, 84 plus a number equals 81. What is that number? We start by converting this word problem into an equation where "what" is what we want to solve:

84 + what = 81

To solve this equation, we first add -84 to each side of the equal sign like this:

84 - 84 + what = 81 - 84

Then, we do the calculation to get the answer to "84 plus what equals 81?" as follows:

What = -3

The answer to "84 plus what equals 81?" is -3. You know this answer is correct because 84 plus -3 equals 81.

Plus What Equals Calculator
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84 plus what equals 82?
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